Recently we added a support beam and new support wall in basement due to sagging floor trusses and lots of vibration when walking and jumping. We also added some Hvac to the room, they ended up cutting our strongback lateral support 2x6 board. Shortly after we did that, we felt constant floor tremors. We are hoping we did not damage our truss supports. The floor is much stronger now but any guidance on the tremors would be appreciated.

We did not take any pictures and it is now covered with drywall. But the board was cut in 2 places and the tremors happen continuously about every 12-17 seconds. If I am moving around the house I do not notice them but I do when I am laying in our bed and that is close to where the board was cut. Not sure what to do?

Tremors, Strongback, I can’t see just as Neil cant what was cut and or how much damage was done. I see thru your wording those some words of real concern though. I think we both have seen in the past how little regard some HVAC people have for structure though and that makes the hair on the back of the neck stand up.

Did you have the structural repair done by a pro and was there an engineer involved? Was there any inspection done or questions raised when the HVAC guys needed to remove structure?

Bottom line is you shouldn’t be feeling tremors in your house. I think you need to open the drywall and take a look that’s what I would do.

Sorry no pictures. We did not have an engineer or inspection done. Our contractor made the decision for them to cut the board, he did not think we needed since we we're have more support added, beam and a wall. but it was completely cut in and a 2 sections were removed for the duct work to fit. Not sure but I think the ducts were suspended.

In some of my research the strongback lateral support 2x6 board is for lateral movement so there is less moment when walking. But my concern is mostly support. We did not raise the floor to be level since we had a lot of stuff done on the main floor. I just hope that our trusses do not turn or twist under stress.

I would bring the contractor back out and tell him your thoughts and have him feel the movement and see what he says. If he made the call on cutting the structure and that's really what is causing it he should make it right.

So if I am right you have trusses like this photo and they have cut out one or some of the angle braces. I have not worked with this stuff but with roof trusses any cut or changes have to be certified by the truss companies engineer. This would be a question for the people who made the trusses. Their name will be on the side of the trusses and if you can't find that the cities permit department will have a copy of the original engineers report and that will have the name of the company.